Rubber-impregnated paper and process of making the same



Feb. 21, 1928. 1,660,204

. K. L. MOSES RUBBER IMPREGNATED PAPER AND PROCESS OF MAKING THE SAME Original Filed March 9, 1925 Fig. 1.

31 H vs. n'fim r. Mime. Mmsea Patented Feb. 21, 1928.

UNITED STATES KIRKE L. MOSES, 0F BROOKLINE, MASSACHUSETTS.

BUBBER-IMPREGNATED PAPER AND PROCESS OF MAKING THE SAME.

Application filed March 9, 1925, Serial No. 14,004. Renewed July 18, 1927.

This invention relates to the class of products which result from impregnating a paper base with rubber-containing liquids, such for instance as rubber-containing latex, with or without compounding ingredients or additions of glycerine or other hygroscopic material; or dispersions, suspensions or emulsions of rubber or compounded rubber. A. product of this sort is considerably tougher and has considerably higher tear-resisting properties than a similar paper product which has not been so impregnated.

One object of my present invention is to provide an improved method of treating a product of this type by which its tear-resisting qualities can be still further increased and also to provide an improved product which results from such process.

I have discovered that if a paper product formed by impregnating a sheet or web of paper with a rubber-containing liquid is subjected to a stretching action or a rubbing action or both or is otherwise manipulated and worked, its tear-resisting properties will be considerably increased, and my improved process, therefore, includes the impregnating of a paper base with the rubber-containing liquid and after the impregnated paper has been dried subjecting it to suiiicient tension to stretch it, or rubbing it, or otherwise working or treating it thereby to give it the increased tensile strength.

In order to give an understanding of my invention I have illustrated in the drawings diagrammatically some ways of practising the invention which will now be described after which the novel features will be pointed out in the appended claims.

Fig. 1 is a diagrammatic view showing the process of impregnating the paper with the rubber-containing liquid;

Figs. 2, 3, 4, 5, 6 and 7 show diagrammatically different devices which may be used for stretching, rubbing or otherwise working the impregnated paper to develop the increased tensile strength.

While the invention is applicable to any paper which has been impregnated with rubber-containing liquid yet it is particularly applicable to an impregnated paper which contains a relatively high percentage of the solid constituents of latex or rubber, such for instance as would result from impregnating with rubber a porous (paper in which the fibres are lggsely matte together, A paper of this sort is well adapted for rubber impregnating because of its porous and loosely matted condition.

In Fig. l which illustrates diagrammatically an impregnating apparatus 1 indicates a web of paper to be impregnated which is shown as being drawn from a roll 2 and as being passed through an impregnating bath 3 contained in a tank or vat 4. The paper is passed over a guide roll 5 and between squeeze rolls 6 which are submerged in the bath 3 and thence through other squeeze rolls 7 which results in removing surplus liquid from the impregnated paper. After coming from the bath the paper is dried in any usual way as by festooning it over supporting bars 8 in a drying room.

After the paper has been dried it is rolled up into a roll as shown at 9. While a paper impregnated in this way has greatly increased tear-resisting properties over an ordinary paper which has not been impregnated yet by furthertreating the paper, as will be now described, its tear-resisting properties can be still further increased.

One way of securing this increase is by subjecting the paper to sufiicient tension to stretch it or produce a distortion therein in the plane of the paper.

Another way is to subject the paper to a rubbing action with more or less pressure. Good results are also secured by subjecting the paper to a combined stretching and rubbing action.

One apparatus by which this step of the process might be secured is illustrated in Fig. 2 in which the impregnated paper 10 is taken from a roll 9 and passed around a bar 11 and is then wound up on another roll 12. The roll 9 is provided with suitable tensioning means 40 so that the paper 10 is subjected to more or less tension as it is withdrawn from the roll 9. The two rolls 9 and 12 are preferably so situated relative to the bar-11 that the paper will be drawn more or less around the bar. With this arrangement the web of paper is subjected to tension which will be so adjusted that it is sufiicient to stretch the paper somewhat, and one face of the paper will be subjected to a rubbing action as it is drawn around the bar 11. This combined rubbing and stretching serves to increase the tear-resisting properties of the paper. v

In Fig. 3 a similar apparatus is shown except that the bar around which the paper is drawn and which is indicated at 13 has a rounded angular edge over which the paper passes instead of the circular surface of the rod or' bar 11. In Fig. 3 also I have shown a presser roll l-twhich may have either a hard or a \'ieldlng body and which is constructed to apply more or less pressure to the paper as it is passing over the bar 13. The roll has a. surface movement in the direction in which the paper moves.

In Fig. 4 an apparatus is shown for treating the impregnated paper which includes a member 15 having a concave surface lti which is provided with one or more ribs 17 and which also includes a presser roll 18 having a yielding body and adapted to press the paper against the rib or ribs 17. This roll is positively driven with a surface speed equal to that at which the paper is fed. The pressure of the roll 18 will preferably be sufficient so that the ribs will be slightly indented in the surface of the roll. The impregnated paper 10 is led from the roll 9 between the presser roll 18 and the rib 17 and is wound upon a driven roll 12. The roll 9 will have more or lesstension applied thereto for the purpose of subjecting the web of paper to the sufficient tension to stretch the same. As the web of paper passes between the roll 18 and the ribs 17 it receives a rubbing action on one face and also is Worked more or less which, together with the tension or stretch to which the paper is subjected, results in increasing thete'ar-resisting properties.

In the device above described the paper is rubbed on one face only. In Fig. 5 I have shown an apparatus whereby the rubbing action will be applied to both faces ofv the paper web. In this device the impregnated paper 10 is taken from the roll 9 and passed around the two bars 19 and 20 which are situated on opposite sides of the web, said bars being so placed relative to the direction of movement of the web that the impregnated web is bent around each bar. The roll 9 in this case also will be subjected to sufliclent tension to apply .the necessary stretch to the paper and as the paper is drawn through the apparatus it receives not only the tension suflicient to stretch it but also receives a rubbing action on each face.

Another device for producing the desired result is indicated in Fig. 6 wherein the web of paper 10 is passed under an idle roll 21 and over the edge of a rubbing member 22.

The roll 21 is closely adjacent the member 22 so that the web of paper is bent more or less sharply as it passes over the edge of" the rubbing member 22. As the paper is drawn from the tension roll 9 and wound up onto the driven roller 12 one face of the paper will be subjected to a rubbing action and the entire web will be subjected to the necessary tension to stretch it.

Another way of treating the paper is shown inFig. 7 wherein the paper 18 drawn across the corner of a stationary bar 23 and is pressed against and bent laterally around the edge of said bar by a yielding presser roll 2% which is pressed against the bar with sutiicient pressure so that the edge of the bar will be indented in the roll slightly. As the. web of paper is withdrawn from the tensioned roll 9 and wound up on the driven roll 12 it will be subjected to suflicient tension to stretch it slightly and one face thereof will also be given a rubbing action.

The above are merely illustrative of some ways in which the before mentioned type of paper may be treated to develop the-increased tear-resisting properties. As stated above, however, this result may be obtained by simply subjecting the paper to suflicient -tension to stretch it or distort it in the plane thereof without subjecting it to a ru bing action, or the result might be secured by subjecting the paper to a rubbing or working action without stretching it.

\Vhere one or both faces of the paper are rubbed I find it is an advantage to apply to the face which is to be rubbed an unctuous material such for instance as wax or soap and good results are obtained by mixing some talc or similar material or powdered mica with the wax or soap. The invention, however, is not limited to the use of the unctuous materialsabove referred .to as any other suitable. material maybe used. Such unctuous material provides a certain degree of lubrication between the paper web and the rubbing member and may be applied to one or both faces as desired. The use of the unctuous material also tends to prevent the rubbing member from roughening the surface of the paper.

A possible theory as to why the tear-resisting properties of the impregnated paper are increased by the above described method is that the stretching 0r rubbing or other working of the impregnated paper tends to rupture the dried protective colloid surrounding the particles of rubber derived from the rubber-containing liquids above referred to so that said particles have a greater rubber-to-rubber contact which possibly increases their adhesion to one another and thus increases the tear-resisting properties of the paper.

I claim: 1. The. process of producing a paper ties which consists in impregnating a web of paper with rubber-contaimng liquid, drying the paper, and subsequently stretching thepaper.

The process of producing a, paper product having high tear-resisting properproduct having high tear-resisting properties which consists in impregnating a web of pa er with rubber-containmg liquid,

ing t e paper, and subsequent y subjecting 5 the paper to a rubbing actlon,

3. The process of treatin rubber impregnated paper to increase its tear-resistmg properties which consists in simultaneously stretching the paper and subjecting it 1 to a rubbing action.

4. The process oftreatin rubber im-' pregnated paper to. increase its tear-resistthe web 1n the direction of the p iii the p ing properties-which consists in distortin 5 A 0d lane thereo paper pr uct compnsmg a. paper 15 base impregnated 'with rubber and distorted ane of the aper. 6. A stretchedru her-impregnated paper having at least one surface coated with unctuous material. I v 20 In testimony whereof, I have signed my name to this specification.

KIRKE L. MOSES. 

